Health workers in West Africa appealed for urgent help in controlling the world's worst Ebola outbreak as the death toll climbed to 932 and Liberia shut a hospital where several staff were infected, including a Spanish priest.

Liberian President Ellen Johnson-Sirleaf declared a state of emergency Wednesday evening, saying the scale of the epidemic represented a threat to state security.

"The government and people of Liberia require extraordinary measures for the very survival of our state and for the protection of the lives of our people," she said in an official statement. "I ... hereby declare a State of Emergency throughout the Republic of Liberia effective as of Aug. 6, 2014 for a period of 90 days."

The outbreak of the haemorrhagic fever has overwhelmed rudimentary healthcare systems and prompted the deployment of troops to quarantine the worst-hit areas in the remote border region of Guinea, Liberia and Sierra Leone.

The World Health Organization (WHO) reported 45 new deaths in the three days to Aug. 4. Its experts began an emergency meeting in Geneva on Wednesday to discuss whether the epidemic constitutes a "Public Health Emergency of International Concern" and to consider new measures to contain it, including the possible use of experimental drug treatments.

"This outbreak is unprecedented and out of control," said Walter Lorenzi, head of medical charity Medecins Sans Frontieres (MSF) in Sierra Leone. "We have a desperate need for other actors on the ground - not in offices or in meetings - but with their rubber gloves on, in the field."

International alarm at the spread of the disease increased when a U.S. citizen died in Nigeria last month after flying there from Liberia. The health minister said on Wednesday that a Nigerian nurse who had treated the deceased Patrick Sawyer had died of Ebola, and five other people were being treated in an isolation ward in Lagos, Africa's largest city.

With doctors on strike, Lagos health commissioner Jide Idris said volunteers were urgently needed to track 70 people who came into contact with Sawyer. Only 27 have so far been traced.

In Saudi Arabia, a man suspected of contracting Ebola during a recent business trip to Sierra Leonealso died early on Wednesday in Jeddah, the Health Ministry said. Saudi Arabia has already suspended pilgrimage visas from West African countries, which could prevent those hoping to visit Mecca for the Haj in early October.

Liberia, where the death toll is rising fastest, is struggling to cope. Many residents are panicking, in some cases casting out the bodies of family members onto the streets of Monrovia to avoid quarantine measures.

Beneath heavy rain, ambulance sirens wailed through the otherwise quiet streets of Monrovia on Wednesday as residents heeded a government request to stay at home for three days of fasting and prayers.

"Everyone is afraid of Ebola. You cannot tell who has Ebola or not. Ebola is not like a cut mark that you can see and run," said Sarah Wehyee as she stocked up on food at the local market in Paynesville, an eastern suburb of Monrovia.

St. Joseph's Catholic hospital was shut down after the Cameroonian hospital director died from Ebola, authorities said. Six staff subsequently tested positive for the disease, including two nuns and 75-year old Spanish priest Miguel Pajares, who is due to be repatriated by a special medical aircraft on Wednesday.

U.S. ALLOWS USE OF EBOLA TEST OVERSEAS

U.S. health regulators on Wednesday authorized the use of an Ebola diagnostic test developed by the Pentagon to help contain the world's worst outbreak of the deadly virus.

The diagnostic test was authorized for use abroad on military personnel, aid workers and emergency responders in laboratories designated by the Department of Defense to respond to the Ebola outbreak, the U.S. Food and Drug Administration said.

The test, called DoD EZ1 Real-time RT-PCR Assay, is designed for use on individuals who have symptoms of Ebola infection, who are at risk for exposure or who may have been exposed. It can take as long as 21 days for symptoms to appear after infections.

The agency can evoke emergency authorization for a medical product it has not approved when there are no adequate alternatives.

The World Health Organization is meeting in Geneva to consider declaring an international health emergency.

U.S. health officials met on Monday in Washington with Guinea President Alpha Conde and senior officials from Liberia and Sierra Leone to discuss the crisis and identify what kind of help they most needed, a State Department official said.

Health and Human Services Secretary Sylvia Mathews Burwell and Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention, met with the leaders on the sidelines of an African Summit.

Frieden was to testify on Thursday at a congressional subcommittee hearing on "Combating the Ebola Threat," along with representatives from the State Department's Africa bureau and the U.S. Agency for International Development.

USAID said it would send a disaster response team, which will include staff from HHS and the CDC, to West Africa to help coordinate Washington's efforts.

The aid agency is also adding $5 million in aid to help international response efforts in the countries hit hardest by the outbreak.

The money will go to programs that help trace people infected with the disease and provide hygiene kits, soap, bleach, gloves and mask to help stem its spread.

"To really protect ourselves, the single most important thing we can do is stop it at the source in Africa," Frieden said on Sunday CBS "Face the Nation." "That's going to protect them and protect us."

TROOPS DEPLOYED IN OPERATION "WHITE SHIELD"

Spain's health ministry denied that one of the nuns - born in Equatorial Guinea but holding Spanish nationality - had tested positive for Ebola. The other nun is Congolese.

"We hope they can evacuate us. It would be marvellous, because we know that, if they take us to Spain, at least we will be in good hands," Pajares told CNN in Spanish this week.